A Flow Cytometry Laboratory was established as a Shared Resource for Morris Cotton Cancer Center in 1981 with a grant from the Fannie E. Rippel Foundation for the purchase of an Ortho System 50 Cytofluorograf. That instrument was replaced in March 1991 by two Becton Dickinson flow cytometers purchased with a grant from the Shared Instrumentation Grant Program (SIG) of the National Center for Research Resources (NIH). Between 1993 and 1995, imaging capability was added to the Flow Cytometry Resource with the acquisition of a confocal imaging system with funding from the SIG program. This equipment established the Flow Cytometry and Cell Imaging Shared Resource to provide both flow and image analysis for NCCC. Since the last application for Core grant renewal, the Shared Resource has received funding from the NIH SIG program, for the purchase of a BD FACSAria sorting flow cytometer and a BD FACSCanto benchtop flow cytometer, and from Dartmouth Medical School for the purchase of a Zeiss stereo fluorescence microscope system. In addition, we have been able to acquire five Macintosh computers and have placed them in a new room to provide users with comfortable access to software for data analysis. At the present time, the Flow Cytometry and Cell Imaging Shared Resource contains four benchtop flow cytometers (two FACScans, a FACSCalibur, and a FACSCanto), two sorting flow cytometers (a FACStar Plus and a FACSAria), a Zeiss 510 Meta laser scanning confocal system, a Compucyte laser scanning cytometer, a Zeiss stereo fluorescence microscope, and a Zeiss fluorescence inverted microscope. In addition, there are six Macintosh workstations and one PC workstation for analysis of data from the flow and imaging instruments. The Flow Cytometry and Cell Imaging Shared Resource is located in a suite of seven rooms in the Borwell Research Building adjacent to the Rubin Building. It is directed by Dr. Alice L. Givan, with Dr. Paul M. Guyre as co-director. Mr. Gary Ward and Mr. Kenneth Orndorff are supervisors of the flow and imaging instruments, respectively. The Shared Resource is being used by 79 Pis, with approximately 300 users from those laboratories. It is funded by a combination of subsidy from the CCSG and chargebacks to individual users.